Lanthanum Doped Barium Cobaltite as a Novel Cathode for Intermediate-temperature SOFC Using Lanthanum Gallate Electrolyte

摘要

A new research and development program to increase the output power density of cell-stack of intermediate-temperature (IT) solid oxide fuel cells (SOFCs) has been started. In order to increase the mechanical strength of the lanthanum gallate electrolyte, starting powder preparation methods and sintering temperature were examined. Manufacturing of dense ceramic bodies with smaller grain sizes was enabled using smaller submicron powder source. An alternative cathode material, lanthanum doped barium cobaltite, and the effects of dispersed Ag particles were investigated. Power generation characteristics were measured as a function of the dopant concentration in Ba{sub}(1-x)La{sub}xCoO{sub}(3-δ).Although observed variation between x = 0.3 and 0.5 was insignificant, the maximum terminal voltage was obtained at x = 0.5. Using Ag-dispersed Ba{sub}0.5La{sub}0.5CoO{sub}(3-δ) cathode, output power density of 0.4 W/cm{sup}2 was obtained at the current density of 0.5 A/cm{sup}2 at 750°C for hydrogen fuel.